So what: The stock had been rallying nicely over the past year on steadily improving sales of consumables, but today's warning is forcing Mr. Market to quickly sober up. While sales of electronics have been the biggest disappointment, sales of food and clothing have also been weak, reigniting worries over Big Lots' ability to compete with gorillas Wal-Mart and Costco.

Now what: For the first quarter, management expects its same-store sales to be slightly negative, versus its previous view of a 2%-4% increase. However, with several analysts expecting management to turn things around over the next couple of quarters, today's pullback seems like a decent opportunity for some relatively quick gains. Of course, for more conservative buy-and-hold types, Big Lots' competitive position remains just too weak to take a long-term position on.